1. Field of the Invention
This invention relates to the detection of the state of a vehicle by a portable device carried by a user and the various actions taken upon the detection of the state.
2. Description of Related Art
People often forget where they park their cars at shopping centers, movie theaters, airports and parking lots in general. It would be very useful to have a portable device that automatically remembers where the car is parked and can tell the user, upon request, where the car is parked and also provide directions to the parked car.
Prior art has discussed using key fobs (U.S. Pat. Nos. 6,694,258, 6,392,592, how do we reference this?) in the car to know when the car has stopped, but this can only work with new cars who in the future may have this system. Furthermore, the user interface to provide guidance back to the car is very limited. Thirdly, copies of keys will not have the location detection system.
Yet other alternative includes getting signal from the car to provide the notice that the car has stopped and also may be the location information (REF? U.S. Pat. No. 6,392,592). Some signals include wireless signals, change in current, opening of the door, etc for example (REF? U.S. Pat. No. 6,650,999).
All of these have the problem of requiring a tight coupling with the car, such that the system installation is cumbersome. Furthermore, if the user drives a car which does not have the same system pre-installed (e.g. rented car), the user cannot use the system.
Also it is not possible to directly use GPS in the above application to detect whether a car is parked or moving because GPS velocity detection cannot be directly used to distinguish between a user walking slowly and a vehicle being driven slowly. Furthermore, the GPS signal may not always be available.
Another related problem deals with blocking certain actions by a user if the user is moving or speeding, for example, blocking texting on cell phones while the user is moving in a car. Using GPS once again has the disadvantage that it cannot be used to detect when a user is walking or a vehicle is being driven slowly. Furthermore, the GPS signal may not always be available. And taking repeated GPS measurements is expensive in terms of battery consumption, and for this application, very frequently repeated measurements would have to be taken in order to timely block certain actions. The battery drain would make GPS essentially useless for this application. These disadvantages of GPS make it unusable in detecting a vehicle's operational state for the various applications described here.
Another related application is the payment of metered parking. The current state of the art requires the user to park the car and walk to a meter and pay the meter; some systems, in addition, require the user to receive a receipt and display the receipt on the dashboard. This manual payment of metered parking is too cumbersome for the user. There have been systems tried in some areas that allow users to pay by phone, however, even these are based on a manual process, in that they require the user to remember to place the calls, enter meter numbers and, in some systems, remember to call again when the vehicle leaves the parking spot.
Another related application is trading parking spaces where members of a group who have parked at a parking spot, inform the other members when they are about to leave their spot, so that other members get a chance to park at the spot. However, this application still requires manual intervention where the user has to use his cellphone to inform the other members.